Background: Non-malignant chronic pain is an increasingly common and complex clinical problem. Primary care physicians are being encouraged by patients, pain specialists, and policy makers to increase the use of chronic opiold therapy as a primary treatment for chronic pain. Some of the major concerns of both physicians and leaders of health care systems are the development of addiction, drug-seeking behavior, and diversion in patients receiving chronic opioid therapy. Specific aims: The proposed study is designed to estimate the current and lifetime prevalence of drug use and dependence in patients receiving chronic narcotics from their primary care physicians. Drugs of interest include licit opioids, illicit opiolds, sedatives, cocaine, stimulants, cannabis, and alcohol. Secondary questions of interest involve levels of pain control on narcotics, co-morbidity issues, health status, and quality of life issues. Methods: A prevalence study will be conducted in six health care systems in Dane and Milwaukee counties in Wisconsin. A sample of 1,000 patients will be recruited from the practices of approximately 200 primary care physicians who work in the six health care systems. Inclusion criteria include taking prescription opioids for at least the past 30 days, age between 18 and 70, a diagnosis of chronic non-malignant pain, and narcotics prescribed by a primary care clinician. Face-to-face interviews will be conducted utilizing the SDSS and PRISM to assess current and lifetime drug addiction. Patients will also complete questionnaires to assess the secondary questions of interest. The physicians will participate in a short interview to assess their current approach to the use of narcotics for chronic pain. Summary: This would be the first large prevalence survey conducted in the US health care system to assess rates of addiction in a primary care chronic pain population.